It's called "overselling"
Dreamhost's control panel is very different in form and function than cPanel, or other commonly encountered web-hosting control panels. It is not "brandable" for re-sellers "out of the box" )though I suppose you could interact with it via programs, if you are a really good programmer . You can give "limited" Control Panel access to users, by assigning them privileges.
There is a great deal of this kind of information in the Dreamhost wiki.